Golf club head with high strength insert

ABSTRACT

An iron type golf club head includes a forged body having a striking face area containing a recess and a high strength insert secured within the recess with an outer surface of the recess being flush with a non-recessed portion of the striking face area. The bottom of the body portion extends rearwardly and upwardly to define an undercut area in the bottom portion behind the insert. Owing to the recess and the undercut area, the weight of the body is distributed around the perimeter and toward the bottom to increase the moment of inertia and decrease rotation of the club head.

[0001] This application is a continuation-in-part of U.S. application Ser. No. 09/615,034 filed Jul. 13, 2000.

BACKGROUND OF THE INVENTION

[0002] The majority of golf club heads of the iron type are made of metal, and many have recesses for receiving an insert for the striking face. In addition, golf club irons are either blades or have a cavity back defined by redistributing the weight of the club head around the perimeter thereof. Perimeter weighted clubs are recognized as increasing the moment of inertia, which increases head stability and lessens head rotation that imparts side spin on the ball. Accordingly, with perimeter weighted clubs, a golfer can hit a straighter shot, even when the ball is not struck in the center or “sweet spot” of the club face.

[0003] Metal golf club irons are generally forged or cast in a mold. Forged club heads are generally softer and provide a greater feel to the golfer, while cast club heads are harder because they can be formed of a higher strength metal than forged club heads. The present invention relates to an improved perimeter weighted club head including an insert for the striking face which is formed of a high strength material.

BRIEF DESCRIPTION OF THE PRIOR ART

[0004] It is known in the patented prior art to provide golf club heads with inserts for the striking face as shown by the U.S. Pat. No. 5,827,131 to Mahaffey and Anderson U.S. Pat. Nos. 5,024,437, 5,094,383, 5,344,140, and 5,261,664. The Mahaffey patent, for example discloses a laminated lightweight insert for golf club heads of both the wood and iron type. The Anderson patents disclose iron type golf club heads having a cast metal head and a forged insert for the striking face. While these prior heads perform satisfactorily, they do not afford the golfer with the desired feel when striking a golf ball.

[0005] Also known in the art are perimeter weighted, cavity back style golf club irons as shown by the U.S. Pat. No. 5,749,795 to Schmidt. As shown therein, an iron golf club head has a first recess extending rearwardly of the striking face and an undercut recess which extends toward the top and bottom wall of the head behind the striking face. Such a head is an improvement over the prior perimeter weighted heads but still lacks a concentration of weight toward the bottom of the head.

SUMMARY OF THE INVENTION

[0006] Accordingly, it is a primary object of the present invention to provide an iron type golf club head including a body having top, bottom, toe and heel portions and a striking face area containing a recess. An insert is secured within the recess, with an outer surface of the insert being flush with a non-recessed portion of the striking face area. The bottom portion of the body comprises the sole of the club head. It extends rearwardly and upwardly from the lower portion of the striking face area in spaced relation from the rear surface of the insert to define an undercut area in the sole behind the insert. The weight of the club head is thus distributed around the perimeter of the body and toward the sole to increase the moment of inertia and decrease rotation of the club head when it strikes a golf ball.

[0007] According to a further object of the invention, the thickness of the sole behind the insert is less than the thickness of the insert. The upwardly extending portion at the rear of the sole terminates in a top wall which is below the vertical midpoint of the body to concentrate the weight of the head toward the bottom. The sole top wall extends between the toe and heel portions of the body and has a convex configuration.

[0008] The head body portion is formed of a forged metal such as carbon steel and the insert is formed of a high strength metal such as hardened steel or a rolled sheet material. With such a combination of materials, the golf club head provides improved feel to the golfer and the high strength insert provides maximum distance to the flight of the golf ball.

BRIEF DESCRIPTION OF THE FIGURES

[0009] Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawings, in which:

[0010]FIG. 1 is a front plan view of the iron type golf club head according to the invention;

[0011]FIG. 2 is a left side view of the head of FIG. 1;

[0012]FIG. 3 is a rear plan view of the head of FIG. 1;

[0013]FIG. 4A is a sectional view of the head taken along line 4-4 of FIG. 1

[0014]FIGS. 4B and 4C are sectional views of alternate embodiments, respectively, of the head taken along line 4-4 of FIG. 1;

[0015]FIG. 5 is a front plan view of an alternate embodiment of the iron type golf club head according to the invention;

[0016]FIG. 6 is a sectional view of the head of FIG. 5 taken along line 6-6;

[0017]FIG. 7 is a front plan view of a further embodiment of the iron type golf club head according to the invention; and

[0018]FIG. 8 is a sectional view of the head of FIG. 7 taken along line 8-8.

DETAILED DESCRIPTION

[0019] As shown in FIGS. 1-3, the golf club head 2 according to the invention includes a frame or body 4 having toe 4 a, heel 4 b, top 4 c and bottom 4 d portions and a striking face area 6 containing a recess 8. An insert 10 is secured within the recess, preferably by welding although other conventional connection methods may be used. The outer surface 10 a of the insert is substantially flush with a non-recessed portion 6 a of the striking face area.

[0020] The body 4 is preferably formed of a forged metal such as carbon steel having an amorphous microstructure and the insert is formed of a high strength material such as hardened steel. One example of a hardened steel is a high chrome content steel known as alpha Maraging steel. Alternatively, the insert can also be formed of a rolled sheet material or a forged metal.

[0021] As shown in FIGS. 3 and 4A, the bottom portion 4 d of the body comprises the sole of the club. The bottom portion extends rearwardly 4 e from the front of the club and upwardly 4 f to a location below the top portion 4 c of the body and spaced from the rear surface of the insert. The sole thus defines an undercut area 12 in the bottom portion of the body behind the insert. The thickness t of the body at the intersection of the rearwardly extending sole bottom portion 4 e and the upwardly extending sole bottom portion 4 f is less than the thickness of the insert. Thus, if the thickness of the insert is between 1.0 and 4.0 mm, and preferably between 2.0 and 2.5 mm, the thickness t is less than the insert thickness. The forward surface of the upwardly extending sole bottom portion 4 f is preferably parallel to the rear surface of the insert so that the width of the undercut area defined between the insert 10 and the portion 4 f is constant. Alternatively, the forward surface of the upwardly extending sole bottom portion 4 f may be angled inwardly as shown in phantom in FIG. 4A so that the width of the undercut area tapers toward the bottom thereof.

[0022] The top wall 4 g of the upwardly extending sole bottom portion 4 f extends between the toe and heel portions of the body and has a convex configuration as shown in FIG. 3. The top wall is arranged below the vertical midpoint of the body so that the weight of the body is concentrated toward the bottom portion of the body. Since the body contains a recess, weight is also distributed about the perimeter of the body. This weight distribution increases the moment of inertia of the club head and decreases rotation of the head when it is used to strike a golf ball.

[0023]FIGS. 4B and 4C illustrate alternate arrangements of rearwardly extending sole bottom portion 4 e of the body. In both embodiments, the bottom portion of the insert extends closer to the bottom of the body than in the embodiment of FIG. 4A and the thickness of the rearwardly extending sole bottom portion 4 e is less than in the embodiment of FIG. 4A.

[0024] In the embodiment of FIG. 4B, a lip 4 h is provided in the rearwardly extending sole bottom portion 4 d to provide a surface against which the back of the insert abuts. Immediately behind the insert, the thickness t of the rearwardly extending sole bottom portion is less than the thickness of the insert. Thus, the deepest portion of the undercut 12 is immediately behind the insert. In the embodiment of FIG. 4A, the deepest portion of the undercut is at the junction of the rearwardly extending sole bottom portion 4 e and the upwardly extending sole bottom portion 4 f.

[0025] In the embodiment of FIG. 4C, the lip 4 h is more pronounced and extends upwardly into the undercut to provide a greater surface against which the insert abuts. The thinnest portion of the rearwardly extending sole bottom portion is right behind the lip 4 h. The thickness t at this location is less than the thickness of the insert.

[0026] In FIGS. 5 and 6, there is shown a further embodiment of the invention wherein the insert 110 extends between the top 104 c and bottom 104 d of the head as shown in FIG. 5. In this embodiment, the insert 110 is adhesively secured to the body or welded thereto, with the weld line extending around the perimeter of the insert. As in the embodiments of FIGS. 4B and 4C, the deepest portion of the undercut is immediately behind the insert. This is due to the fact that the thinnest portion of the rearwardly extending sole bottom portion is directly behind the insert, with the thickness t at this location being less than the thickness of the insert.

[0027] In FIGS. 7 and 8, there is shown a further embodiment of the invention wherein the golf club head has a unitary construction and is preferably formed of a cast metal. The body 204 is similar in configuration to the body of FIGS. 1-3 and thus has toe 204 a, heel 204 b, top 204 c, and bottom 204 d portions. In lieu of an insert, the body has an integral striking face 210. The head bottom portion includes a rearwardly extending sole bottom portion 204 e and an upwardly extending sole bottom portion 204 f which extends between the toe and heel portions to define an undercut region 212 behind the striking face 210. The top wall 204 g of the upwardly extending sole bottom portion 204 f has a convex configuration and is below the vertical midpoint of the body. The thickness t of the sole bottom portion 204 e behind the striking face at the bottom of the undercut portion is less than the thickness of the striking face.

[0028] The iron type golf club head of the invention provides improved feel to the golfer because the forged body is softer and thus provides feedback to the golfer when a ball is struck. Maximum distance in the flight of the ball is obtained by using the higher strength insert. The perimeter weighting of the club provides a larger “sweet spot” in the club striking face so that less precision is required when hitting the ball. The concentration of weight toward the bottom of the head increases the trajectory of the ball and enables the golfer to get the ball airborne from difficult lies. By reducing the thickness of the sole behind the striking face insert, more weight is available for re-distribution toward the perimeter of the club and/or rearward in the sole.

[0029] While the club head of the invention has been described as comprising separate body and striking face insert components, it will be appreciated that the body and striking face can be formed as an integral unit, either cast or forged. The integral head would have the same appearances as in the drawings, except that the striking face would not comprise a separate element.

[0030] While in accordance with the provisions of the patent statute the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modifications may be made without deviating from the inventive concepts set forth above. 

What is claimed is:
 1. A golf club head of the iron type, comprising (a) a body having top, bottom, toe, and heel portions and a striking face area containing a recess; (b) an insert secured within said recess, an outer surface of said insert being substantially flush with a non-recessed portion of said striking face area; and (c) said body bottom portion extending rearwardly and upwardly to a location below the top portion of said body and spaced from a rear surface of said insert to define an undercut area in said bottom portion behind said insert, the thickness of said rearwardly extending bottom portion at the rear of said insert being less that the thickness of said insert, whereby weight is distributed around the perimeter of the body and toward the bottom portion thereof to increase the moment of inertia and decrease rotation of the club head.
 2. A golf club head as defined in claim 1, wherein said upwardly extending bottom portion terminates in a top wall which is below a vertical midpoint of said body.
 3. A golf club head as defined in claim 2, wherein said top wall extends between said toe and heel portions of said body.
 4. A golf club head as defined in claim 3, wherein said top wall has a convex configuration.
 5. A golf club head as defined in claim 1, wherein said body portion is formed of a forged metal.
 6. A golf club head as defined in claim 5, wherein said insert is formed of a high strength metal.
 7. A golf club head as defined in claim 6, wherein said insert is formed of hardened steel.
 8. A golf club head as define in claim 7, wherein said insert is connected with said body by welding.
 9. A golf club head of the iron type, comprising a body having top, bottom, toe, and heel portions and a striking face arranged between said top, bottom, toe and heel portions, said body bottom portion extending rearwardly and upwardly to a location below the top portion of said body and spaced from a rear surface of said striking face portion to define an undercut area in said bottom portion behind said striking face portion, the thickness of said rearwardly extending bottom portion at the rear of said striking face portion being less than the thickness of said striking face portion, whereby weight is distributed around the perimeter of the body and toward the bottom portion thereof to increase the moment of inertia and decrease rotation of the club head.
 10. A golf club head as defined in claim 9, wherein said upwardly extending bottom portion terminates in a top wall which is below a vertical midpoint of said body.
 11. A gold club head as defined in claim 10, wherein said top wall extends between said toe and heel portions of said body.
 12. A golf club head as defined in claim 11, wherein said top wall has a convex configuration.
 13. A golf club head as defined in claim 9, wherein said body is formed of a cast metal.
 14. A golf club head as defined in claim 9, wherein said body is formed of a forged metal. 